Effect of pre-mating nutritional status in red deer (Cervus elaphus scoticus) hinds on the sex ratio of their offspring

Elevated blood urea nitrogen alters the transcriptome of equine embryos

High blood urea nitrogen (BUN) in cows and ewes has a negative effect on embryo development; however, no comparable studies have been published in mares. The aims of the present study were to evaluate the effects of high BUN on blastocoele fluid, systemic progesterone and Day 14 equine embryos. When a follicle with a mean (±s.e.m.) diameter of 25±3mm was detected, mares were administered urea (0.4g kg-1) with sweet feed and molasses (n=9) or sweet feed and molasses alone (control; n=10). Blood samples were collected every other day. Mares were subjected to AI and the day ovulation was detected was designated as Day 0. Embryos were collected on Day 14 (urea-treated, n=5 embryos; control, n=7 embryos). There was an increase in systemic BUN in the urea-treated group compared with control (P<0.05), with no difference in progesterone concentrations. There were no differences between the two groups in embryo recovery or embryo size. Urea concentrations in the blastocoele fluid tended to be higher in the urea-treated mares, with a strong correlation with plasma BUN. However, there was no difference in the osmolality or pH of the blastocoele fluid between the two groups. Differentially expressed genes in Day 14 embryos from urea-treated mares analysed by RNA sequencing were involved in neurological development, urea transport, vascular remodelling and adhesion. In conclusion, oral urea treatment in mares increased BUN and induced transcriptome changes in Day 14 equine embryos of genes important in normal embryo development.

Social rank and reproductive performance in a herd of farmed red deer females (Cervus elaphus)

Hierarchical relationships between individuals determine unequal access to recourses like food and individuals of the other gender, resulting in a higher reproductive success of high-social ranked individuals. Environmental conditions and food availability may determine how strong these effects are. The aim of this work was to determine if social rank of farmed red deer females affect the reproductive results of a hormonal oestrous synchronisation treatment with ad libitum food. The studied responses included the time to oestrus onset, percentage of females that came into oestrus, conception and calving rates, gestation length, and calf gender. The study was performed during autumn on a research farm located in Mexico (20°36ʹ N, 99°55ʹ W). Forty-nine adult red deer females were assigned to two replications of 21 and 28 animals respectively and were allocated into independent paddocks with ad libitum food and water availability. Oestrous cycles were synchronised with a traditional protocol of intravaginal devices impregnated with progesterone. Agonistic behaviours between females were recorded (total = 1626 interactions), hierarchical position (Success Index = SI) of each animal was calculated and individuals were categorised as high (n = 13), medium (n = 20) or low-ranked (n = 16) individuals. Reproductive data were recorded during the 5 days after the oestrous synchronisation treatment and during the calving period. Any of the recorded responses differ between HR, MR and LR females. Female SI, age and bodyweight were not related with the probability of coming into oestrus, result pregnant, and giving birth to a male calf. Thirty-seven (78.5%) females of this study gave birth. From these calves, 15 were males and 22 were females. Due to high percentage of females in oestrus that gave birth (85.7%), it was not possible to detect the relationship between female SI, age, and bodyweight with the conception rate. Female SI, age and bodyweight were unrelated to time to oestrus onset (r2 = 0.09; P = 0.17), and to gestation length (r2 = 0.10; P = 0.20). In conclusion, with ad libitum high quality food, the social rank of red deer hinds did not affect the time to oestrus onset, percentage of females that came into oestrus, gestation length, calving and conception rates, and offspring sex ratio after an oestrous synchronisation hormonal treatment.

Effect of concentrate supplementation on feed consumption, nutrient utilization and blood metabolite profile in captive spotted deer (Axis axis) fed oat (Avena sativa) and berseem (Trifolium alexandrinum) fodders based diet

This experiment was conducted to determine the optimum level of a maize-soybean meal-wheat bran concentrate supplement fed to captive spotted deer fed an oat and berseem fodder-based diet. Twelve adult spotted deer [64-76 kg body weight (BW)] were distributed into three groups of four each and were housed individually. A diet consisting of 5 kg of oat fodder and 5.5 kg of berseem fodder was offered to each one of the experimental animals. The animal in group I received no supplementary concentrate, whereas, those in groups II and III received 0.5 and 1 kg of supplementary concentrate, respectively. A 60 days digestibility trial was conducted with a 5 days collection period on Days 55-59 of the trial. Blood samples were collected from all animals on Day 60 of the experiment. Average daily dry matter intake (DMI) was 1,224, 1,613, and 1,574 g/day in groups I, II, and III, respectively. Dry matter (DM) and organic matter (OM) intake was lowest (P < 0.01) in group I. Intake of P, Cu, and Zn was highest (P < 0.01) in group III, followed by groups II and I. Digestibility of neutral detergent fiber was highest (P < 0.05) in group II. Digestibility of OM and CP was lowest (P < 0.05) in group I. Digestibility of gross energy was highest (P < 0.01) in group III (74.9%), followed by groups II (69.3%) and I (66.2%). Digestible energy (DE) intake (kcal/kg BW(0.75) ) was highest (P < 0.01) in group III (195.4), followed by groups II (180.9) and I (129.8). Initial BW was 72.7, 72.5, and 71.0 kg, whereas, final BW was 71.0, 72.7, and 73.5 kg, in groups I, II and III, respectively. Average daily change in body mass was significantly (P < 0.01) different among the groups. The body mass was lost (-29.2 g/day), maintained (4.1 g/day) and gained (41.6 g/day) in groups I, II, and III, respectively. Blood glucose and cholesterol concentration was highest (P < 0.05) in group III, followed by groups II and I. Serum concentration of Cu and Zn was highest (P < 0.05) in group III, followed by groups II and I. Supplementation of forage only diet with 0.5 kg of concentrate mixture increased intake and digestibility of nutrients, without change in body mass. Animals fed 1 kg of supplementary concentrate received energy in excess of requirements, were consistently gaining body mass and were prone to obesity. Thus, it is a right strategy to supplement forage only diet of captive spotted deer with 0.5 kg of concentrate.

Sex-dependent insulin like growth factor-1 expression in preattachment equine embryos

An adjustment of sex ratio of offspring to the conditions present at conception is seen in many mammals including horses. This depends on preferential survival of male embryos under conditions of high energy intake. In several species, growth factors including insulin like growth factor (IGF)-1 have been shown to promote embryonic development by decreasing apoptosis and increasing cell proliferation. We hypothesized that sex-related differences in IGF-1 expression in equine embryos during the phase of maternal recognition of pregnancy might exist and thus contribute to preferential survival of embryos from either of both sexes under specific environmental conditions. Insulin like growth factor-1 mRNA expression of in vivo-produced equine embryos on different days of pregnancy (Day 8, N = 6; Day 10, N = 8; Day 12, N = 14) was analyzed. Insulin like growth factor-1 mRNA expression was evaluated by reverse transcription quantitative polymerase chain reaction. The sex of the embryo was determined by detection of X-inactivation specific transcript (Xist) RNA and equine sex determining region of the Y chromosome DNA. Embryos positive for Xist expression were classified as female, and Xist negative and equine sex determining region of the Y chromosome positive embryos were classified as male. From 28 embryos tested, 15 (54%) showed positive Xist expression and were thus classified as female. Insulin like growth factor-1 mRNA expression was influenced by sex (P = 0.01) but not by day of pregnancy (relative expression of IGF-1 in relation to β-actin, Day 8: male 5.1 ± 2.1, female 11.4; Day 10: male 5.2 ± 1.6, female 17.4 ± 6.7; Day 12: male 2.6 ± 0.3, female 11.6 ± 2.4). Results demonstrate an increased expression of IGF-1 in female equine embryos. Sex-related influences on expression of the IGF system are probably related to a gradual X chromosome inactivation.